问题 单项选择题

运输成本最低廉的运输方式是()

A、铁路运输 

B、公路运输 

C、航空运输 

D、水路运输

答案

参考答案:D

探究题

实验题(5分)

修正液是同学们常用的一种文具,打开后,有刺激性的气味。我们不禁要问:修正液对人体有害吗?请你设计一个实验,对这个问题进行探讨。

【实验材料】修正液、小白鼠6只、米饭、水、关小白鼠的笼子。

【提出问题】                                                                      

【作出假设】                                                                      

【设计方案】                                                                                                                                       

                                                                                                                                   

                                                                                                                                 

【现象】                                                                            

【结论】                                                                         

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